1. Field of the Invention
This invention relates to high performance ballistic composites that have improved flexibility, and to a process for making the same.
2. Description of the Related Art
Ballistic resistant products for vests and the like are known in the art. Many of these products are based on high tenacity fibers, such as extended chain polyethylene fibers. Body armor, such as bullet-resistant vests, may be formed from rigid composites and/or flexible composites.
Rigid body armor provides good ballistic resistance, but is also very stiff and relatively bulky. As a result, in general, rigid body armor garments (e.g., vests) are usually less comfortable to wear than flexible body armor garments. Rigid body armor is also referred to as “hard” armor, which has been defined in the art (see, for example, U.S. Pat. No. 5,690,526) to mean an article, such as a helmet or panels for military vehicles, which has sufficient mechanical strength so that it maintains structural rigidity when subjected to a significant amount of stress and is capable of being free-standing without collapsing. In contrast to such rigid or hard armor, is flexible or “soft” armor which does not have the attributes associated with the hard armor previously mentioned. Although flexible body armor based on high tenacity fibers has excellent service experience, its ballistic performance is generally not as high as that of hard armor. If higher ballistic performance is desired in flexible armor, generally speaking the flexibility of such armor is decreased.
Various attempts have been made to produce flexible ballistic composites, such as providing permanent creases in a fibrous web as is disclosed in U.S. Pat. No. 5,124,195 to Harpell et al., and providing textured surfaces as is described in U.S. Pat. No. 5,567,498 to McCarter et al.
It would be desirable to provide a flexible ballistic composite material which has improved flexibility and also improved ballistic performance. It would also be desirable to provide an armor product, such as body armor, based on such a material which likewise has improved flexibility and ballistic performance. Such armor desirably would be comfortable to wear and not costly to manufacture.